JP2005214074A - Cylinder block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder block capable of minimizing the lowering of the roundness of the cylinder bore of a cylinder block in the split type cylinder block. <P>SOLUTION: This cylinder block 10 is dividedly formed of a cylinder liner part 21 forming a wall surface on the cylinder liner 12 side and a cylinder outer wall part 32 forming an outer wall surrounding the portion thereof forming a water jacket 13 on both sides of the portion forming the water jacket 13 formed around the cylinder liner 12. A projected part 28 is formed on the outer peripheral surface 24 of the cylinder liner part 21, and the portions thereof corresponding to the projected parts 28 of the cylinder liner part 21 and the cylinder outer wall part 32 are integrally fixed to each other by bolting. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cylinder block of an internal combustion engine.

  As a cylinder block of an internal combustion engine, a cylinder liner part constituting a wall surface on the cylinder side and a cylinder constituting an outer wall surrounding the part serving as the water jacket, with a part serving as a water jacket formed around the cylinder as a boundary A device that is divided into an outer wall portion is known (see, for example, Patent Document 1).

In such a structure in which the cylinder block is divided and formed, a method of press-fitting the cylinder liner portion into the cylinder outer wall portion among these divided bodies is generally employed as an assembling method. By integrating the two divided bodies by such press-fitting, the two divided bodies can be easily combined.
Japanese Patent No. 2759987

  In such a method using press-fitting, although it is possible to bond relatively firmly, a large force acts on the press-fitted portion during press-fitting, and there is a concern that the residual stress may adversely affect the state after the press-fitting. .

  By the way, the cylinder bore of the cylinder block usually has a great influence on the engine performance, specifically, compression ratio, oil consumption rate, fuel consumption, and the like. Therefore, if the cylinder is deformed by the adverse effects of the force during press-fitting and the residual stress and the roundness is lowered, the above-mentioned adverse effects caused by the cylinder cannot be ignored.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a cylinder block that can suppress a decrease in roundness of a cylinder bore in a split cylinder block as much as possible.

In the following, means for achieving the above object and its effects are described.
In the first aspect of the present invention, a cylinder liner portion that forms a wall surface on the cylinder side and an outer wall that surrounds the portion that becomes the water jacket are formed with a boundary that becomes a water jacket formed around the cylinder as a boundary. The cylinder outer wall portion is divided and formed, and a convex portion is formed on one of the outer peripheral surface of the cylinder liner portion and the inner peripheral surface of the cylinder outer wall portion. The gist is that the bolt is fastened and fixed integrally.

  According to the above configuration, when the cylinder block is formed, the cylinder liner portion can be inserted into the cylinder outer wall portion without applying an excessive force, and they can be fixed to each other by bolt fastening. Therefore, it is possible to suppress an excessive force from acting on the cylinder block during or after the formation, and it is possible to suppress deformation due to the force. Therefore, it is possible to suppress the decrease in roundness in the cylinder bore as much as possible. In the above configuration, the convex portion is formed only on one of the outer peripheral surface of the cylinder liner portion and the inner peripheral surface of the cylinder outer wall portion, and the convex portion is the outer peripheral surface of the cylinder liner portion and the cylinder. The structure formed in both the internal peripheral surfaces of an outer wall part is also employable.

  According to a second aspect of the present invention, in the cylinder block according to the first aspect, the convex portion formed on one of the outer peripheral surface of the cylinder liner portion and the inner peripheral surface of the cylinder outer wall portion is in contact with the other. The main point is to be contacted.

  In the above configuration, the convex portion formed on one of the outer peripheral surface of the cylinder liner portion and the inner peripheral surface of the cylinder outer wall portion is brought into contact with the other. Therefore, the tightening force of the bolt is restricted by this contact, and it is possible to suppress deformation of the outer peripheral surface of the cylinder liner portion and the inner peripheral surface of the cylinder outer wall portion due to excessive tightening. Furthermore, the sealing performance at the bolt fastening portion can be improved by the contact force.

Further, the invention according to claim 3 is the cylinder block according to claim 1 or 2, wherein the convex portion extends in a belt shape.
According to the said structure, the said convex part can be functioned as a reinforcement rib, and the rigidity of a cylinder liner part, a cylinder outer wall part, and a cylinder block can be improved suitably. In addition, through the setting of the extending mode, the flow direction of the cooling water in the water jacket can be set, and as a result, the cooling performance can be improved.

  According to a fourth aspect of the present invention, in the cylinder block according to the third aspect, the convex portion extends spirally on one of the outer peripheral surface of the cylinder liner portion and the inner peripheral surface of the cylinder outer wall portion. The gist is to be established.

  According to the above configuration, the cooling water can be smoothly flowed in the concave portions formed between the convex portions on the entire outer wall of the cylinder liner portion, and the cooling efficiency can be improved. Will be able to.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment embodying a cylinder block according to the present invention will be described in detail with reference to the drawings.
The cylinder block according to the present embodiment is used for an in-line four-cylinder internal combustion engine.

FIG. 1A shows a perspective structure of a cylinder block according to the present embodiment, and FIG. 1B shows a side structure thereof.
As shown in these drawings, in the cylinder block 10 according to the present embodiment, four cylinders (cylinders 12) are formed in the upper part, and a crankcase part 31 is provided in the lower part. The crankcase portion 31 forms a so-called crankcase and houses a crankshaft (not shown) together with an oil pan (not shown) attached below the crankcase.

The cylinder block 10 has a divided structure that is divided into two molded bodies of an inner peripheral block 20 and an outer peripheral block 30.
Hereinafter, the inner peripheral block 20 and the outer peripheral block 30 will be described separately.

First, the inner peripheral block 20 will be described.
2A shows a perspective structure of the inner peripheral block 20, and FIG. 2B shows a side structure thereof.

  As shown in these drawings, the inner peripheral block 20 constitutes a cylinder liner portion 21 and an upper deck portion 22 of the cylinder block 10. The inner peripheral block 20 is made of, for example, an aluminum alloy or a magnesium alloy, and is integrally cast using a die casting method or the like.

  The cylinder liner portion 21 is formed in a shape in which four circular pipe bodies serving as cylinder liners are continuously connected. An inner peripheral surface 23 of each circular tube body constitutes a peripheral wall surface of the cylinder 12 (FIG. 1A), and an outer peripheral surface 24 of the water jacket defined around the cylinder 12 is on the cylinder 12 side. Configure the wall. This water jacket will be described in detail later.

  A protective film made of, for example, cast iron is coated on the inner peripheral surface 23 of the cylinder liner portion 21 that becomes the surface of the cylinder 12 by thermal spraying or the like. Further, a convex portion 28 extending in a strip shape is formed on the outer peripheral surface 24 of the cylinder liner portion 21. Specifically, the convex portion 28 is configured such that the tip of the convex portion 28 contacts the inner peripheral surface 35 of the cylinder outer wall portion 32 in a state where the cylinder liner portion 21 is attached to the cylinder outer wall portion 32, and the outer periphery of the cylinder liner portion 21. The surface 24 is formed to extend spirally. The convex portion 28 functions as a reinforcing rib, thereby increasing the rigidity of the cylinder liner portion 21 and, consequently, the rigidity of the cylinder block 10. Bolt holes 29 are formed in the convex portions 28 corresponding to the respective cylinders 12.

  On the other hand, the upper deck portion 22 is formed in a substantially flat plate shape at the upper end portion of the cylinder liner portion 21. The upper deck portion 22 constitutes the top surface portion of the cylinder block 10. The upper surface of the upper deck portion 22 is a mounting surface 26 on which a cylinder head (not shown) is mounted. When the cylinder head is assembled to the cylinder block 10, the bottom surface of the cylinder head comes into contact. ing. Further, the upper deck portion 22 is formed with a plurality of bolt insertion holes 27 through which head bolts used for fastening the cylinder head and the cylinder block 10 are inserted.

Next, the outer peripheral block 30 will be described.
3A shows a perspective structure of the outer peripheral block 30, and FIG. 3B shows a side structure thereof.

  As shown in these drawings, the outer peripheral block 30 largely constitutes the crankcase portion 31 and the cylinder outer wall portion 32 of the cylinder block 10. A plurality of ribs 11 for reinforcement are formed on the outer periphery of the crankcase portion 31 and the cylinder outer wall portion 32 so as to extend vertically and horizontally. As with the inner peripheral block 20, the outer peripheral block 30 is also made of an aluminum alloy, a magnesium alloy, or the like, and is integrally cast using a die casting method or the like.

  A cylinder outer wall portion 32 is formed on the crankcase portion 31 so as to protrude upward. The cylinder outer wall portion 32 is formed in a substantially annular shape having an inner peripheral surface 35 formed so as to face the outer peripheral surface 24 of the cylinder liner portion 21 of the inner peripheral block 20 described above. This cylinder outer wall part 32 comprises the outer wall surrounding the part used as the said water jacket.

  Further, a flange 36 is formed at the upper end of the cylinder outer wall 32 so as to protrude from the outer periphery to the cylinder bore outer periphery. The top surface of the cylinder outer wall portion 32 in which the flange 36 is formed serves as a receiving surface 32 a that abuts and supports the upper deck portion 22 (FIG. 2) of the inner peripheral block 20.

  The cylinder outer wall 32 is provided with a plurality of bolt fastening holes 37 through which the head bolts are inserted. Further, it corresponds to a bolt hole 29 (FIG. 2 (a)) formed on the convex portion 28 of the cylinder liner portion 21 in the state where the cylinder liner portion 21 is assembled on the side portion of the cylinder outer wall portion 32. A through hole 39 is formed at each position.

FIG. 4 shows a sectional structure of the cylinder block 10 taken along line IV-IV in FIG.
As shown in the figure, the cylinder liner portion 21 of the inner peripheral block 20 is inserted and mounted in the cylinder outer wall portion 32 from above. By this mounting, a gap is formed between the opposing surfaces of the outer peripheral surface 24 of the cylinder liner portion 21 and the inner peripheral surface 35 of the cylinder outer wall portion 32. The cylinder liner portion 21 is inserted into the cylinder outer wall portion 32 up to a position where the receiving surface 32a at the upper portion of the cylinder outer wall portion 32 and the lower surface of the upper deck portion 22 come into contact with each other. The outer peripheral surface 24 below the cylinder liner portion 21 is in contact with the inner peripheral surface 35 below the cylinder outer wall portion 32. That is, the lower portion of the cylinder liner portion 21 is supported by the lower portion of the cylinder outer wall portion 32.

  Thus, the water jacket 13 described above is defined by the outer peripheral surface 24 of the cylinder liner portion 21, the inner peripheral surface 35 of the cylinder outer wall portion 32, and the lower surface of the upper deck portion 22 around the cylinder 12 in the cylinder block 10. It has become so. In addition, between the opposing surfaces of the lower surface of the upper deck portion 22 and the receiving surface 32a of the cylinder outer wall portion 32, and between the opposing surfaces of the outer peripheral surface 24 below the cylinder liner portion 21 and the inner peripheral surface 35 below the cylinder outer wall portion 32. Each is provided with a sealing material (not shown). Thereby, the leakage of the cooling water from between the opposing surfaces to the outside of the water jacket 13 is sealed.

  Here, as described above, the convex portion 28 is formed on the cylinder liner portion 21 so as to extend spirally on the outer peripheral surface 24 and so that the tip thereof contacts the inner peripheral surface 35 of the cylinder outer wall portion 32. Has been. Therefore, the inside of the water jacket 13 is partitioned by the convex portion 28 into a passage shape extending spirally along the outer wall of the cylinder liner portion 21. And the cooling water is supplied and discharged | emitted so that it may flow toward the upper end from the lower end of such a water jacket 13, or toward the lower end from the upper end. As a result, the cooling water in the water jacket 13 can flow smoothly without stagnation, and the cooling efficiency can be improved.

  Further, in the present embodiment, with the cylinder liner portion 21 inserted and mounted inside the cylinder outer wall portion 32, the bolts 14 are formed on the cylinder outer wall portion 32 as shown in FIG. The through holes 39 are inserted into the bolt holes 29 formed in the convex portions 28 of the cylinder liner portion 21. That is, the cylinder liner portion 21 and the cylinder outer wall portion 32 are integrally fixed by bolt fastening.

  In the present embodiment, since the convex portion 28 is in contact with the inner peripheral surface 35 of the cylinder outer wall portion 32, the tightening force of the bolt 14 is restricted by this contact at the time of the bolt tightening, and due to excessive tightening. It is possible to suppress deformation of the outer peripheral surface 24 of the cylinder liner portion 21 and the inner peripheral surface 35 of the cylinder outer wall portion 32. Furthermore, the sealing performance at the bolt fastening portion can be improved by the contact force.

  In such a cylinder block 10, the cylinder liner portion 21 can be attached to the cylinder outer wall portion 32 without applying an excessive force to the cylinder liner portion 21 or the cylinder outer wall portion 32 without using the aforementioned press-fitting method. And can be fixed by bolt fastening. For this reason, it is possible to suppress an excessive force from acting on the cylinder block 10 during or after the formation of the cylinder block 10, suppress deformation caused by the force, and suppress a decrease in roundness of the cylinder bore as much as possible. become able to.

As described above, according to the present embodiment, the effects described below can be obtained.
(1) It becomes possible to suppress a decrease in roundness in the cylinder bore as much as possible.

  (2) The convex portion 28 is formed so that its tip abuts against the inner peripheral surface 35 of the cylinder outer wall portion 32 in a state where the cylinder liner portion 21 is attached to the cylinder outer wall portion 32. For this reason, when tightening the bolt, the tightening force of the bolt 14 is restricted by this contact, and the outer peripheral surface 24 of the cylinder liner portion 21 and the inner peripheral surface 35 of the cylinder outer wall portion 32 are prevented from being deformed due to excessive tightening. It becomes possible to do. Furthermore, the sealing performance at the bolt fastening portion can be improved by the contact force.

  (3) Since the convex portion 28 is extended in a belt shape, the convex portion 28 can function as a reinforcing rib, and the rigidity of the cylinder liner portion 21 and the rigidity of the cylinder block 10 can be suitably increased. it can.

  (4) Since the convex portion 28 is formed to extend spirally on the outer peripheral surface 24 of the cylinder liner portion 21, the cooling water can be smoothly flowed in the water jacket 13 without stagnation, thereby improving the cooling efficiency. It becomes possible to plan.

The embodiment described above may be modified as follows.
In the above embodiment, when there is a concern about the leakage of cooling water to the outside of the water jacket 13 through the through hole 39 of the cylinder outer wall portion 32, the inner peripheral surface 35 of the cylinder outer wall portion 32 and the convex portion 28 A sealing material such as an O-ring may be interposed between the front end surface or between the bolt 14 and the cylinder outer wall portion 32.

  In the above embodiment, the inner peripheral block 20 and the outer peripheral block 30 are made of an aluminum alloy or a magnesium alloy. However, for example, one or both of them may be made of cast iron. Also good. For example, if the mechanical strength of the entire cylinder block 10 is ensured to some extent on the outer peripheral block 30 side, the inner peripheral block 20 may be made of a material that is relatively difficult to secure strength, such as ceramics or sintered alloy. It is done. Further, for the outer peripheral block 30 that is not directly exposed to the combustion gas in the cylinder 12, the use of a material having a relatively low heat resistance such as a resin material may be considered.

-In above-mentioned embodiment, although the inner peripheral block 20 and the outer peripheral block 30 were shape | molded with the die-casting manufacturing method, those manufacturing methods are not restricted to this, You may change arbitrarily.
In the above embodiment, the protective film made of iron or the like is formed on the wall surface of the cylinder 12 by thermal spraying, but such processing may not be performed. If the inner peripheral block 20 is formed of a material having sufficient wear resistance such as cast iron, the base material can be used as the surface of the cylinder 12 as it is.

  -In above-mentioned embodiment, although the convex part 28 was extended helically, the extending aspect can be changed suitably. By extending the convex portion 28 in a band shape, the flow direction of the cooling water in the water jacket 13 can be arbitrarily set while increasing the rigidity of the cylinder block 10.

  Further, if the rigidity of the cylinder block 10 and the smooth fluidity of the cooling water in the water jacket 13 are ensured, the convex portion 28 is located in the cylinder liner portion 21 and is connected to the cylinder outer wall portion 32. It is also possible to project and form only the part for mounting.

  In the above embodiment, the convex portion 28 is formed such that the tip thereof is in contact with the inner peripheral surface 35 of the cylinder outer wall portion 32. If the space between the outer peripheral surface 24 of the cylinder liner portion 21 and the inner peripheral surface of the cylinder outer wall portion 32, as well as the capacity of the water jacket 13 and the strength of the cylinder liner portion 21 can be ensured, the tip of the convex portion It is also possible to form the convex portion in such a manner that the inner peripheral surface 35 of the cylinder outer wall portion 32 is separated.

  In the above embodiment, the convex portion is formed on the cylinder liner portion 21, but instead, the convex portion 48 is provided on the inner peripheral surface 35 of the cylinder outer wall portion 32 as shown in FIG. 5 as an example. You may make it form. Further, as shown in FIG. 6, it is possible to form a convex portion 28 ′ on the outer peripheral surface 24 of the cylinder liner portion 21 and a convex portion 48 ′ on the inner peripheral surface 35 of the cylinder outer wall portion 32. It is.

  In the above embodiment, the case where the present invention is applied to a cylinder block used in an in-line four-cylinder internal combustion engine has been described. The present invention is an internal combustion engine having three or less or five or more cylinders, a V-type internal combustion engine, a horizontally opposed internal combustion engine, etc. The present invention can be applied to any type of internal combustion engine.

The figure which shows together the (a) perspective structure and (b) side structure about one Embodiment of the cylinder block concerning this invention. The figure which shows together (a) perspective structure and (b) side structure of the inner peripheral block which comprises the cylinder block. The figure which shows together (a) perspective structure and (b) side structure of the outer periphery block which comprises the cylinder block. The figure which shows together (a) cross-section structure along the IV-IV line of FIG. 1, and (b) the partial enlarged structure. The expanded sectional view which shows the convex part concerning other embodiment of this invention, and its periphery structure. The expanded sectional view which shows the convex part concerning other embodiment of this invention, and its periphery structure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Cylinder block, 11 ... Rib, 12 ... Cylinder, 13 ... Water jacket, 14 ... Bolt, 20 ... Inner peripheral block, 21 ... Cylinder liner part, 22 ... Upper deck part, 23 ... Inner peripheral surface, 24 ... Outer peripheral surface, 26: mounting surface, 27: bolt insertion hole, 28, 28 ', 48, 48' ... convex portion, 29 ... bolt hole, 30 ... outer peripheral block, 31 ... crankcase portion, 32 ... cylinder outer wall portion, 32a ... receiving 35, inner peripheral surface, 36, flange, 37, bolt fastening hole, 39, through hole.

Claims (4)

With a part to be a water jacket formed around the cylinder as a boundary, a cylinder liner part constituting the wall surface on the cylinder side and a cylinder outer wall part constituting an outer wall surrounding the part to be the water jacket are formed separately. A convex portion is formed on one of the outer peripheral surface of the cylinder liner portion and the inner peripheral surface of the cylinder outer wall portion, and the convex portion and the other formed on one of them are bolted and fixed integrally. Cylinder block characterized by The cylinder block according to claim 1, wherein the convex portion formed on one of the outer peripheral surface of the cylinder liner portion and the inner peripheral surface of the cylinder outer wall portion is in contact with the other. The cylinder block according to claim 1, wherein the convex portion extends in a belt shape. The cylinder block according to claim 3, wherein the convex portion is spirally extended on one surface of an outer peripheral surface of the cylinder liner portion and an inner peripheral surface of the cylinder outer wall portion.

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